1. Technical Field
The present invention relates to a flow cell which is utilized in the fields of handling a trace amount of solution, such as micro-TAS, Lab-on-a-chip, micro-combinatorial chemistry, chemical IC, chemical sensor, biosensor, microanalysis, electrochemical analysis, chromatography, QCM measurement, SPR measurement, ATR measurement, etc. In more detail, the invention relates to a flow cell in which a porous member having a sample-compatible interior is disposed on a sample-incompatible substrate and which does not require means for pumping a liquid from the outside, such as a pump, etc. Also, the invention relates to a flow cell further having a top cover. The invention also relates to a method for manufacturing the above-described flow cell.
2. Background Art
In each of the foregoing fields, there may be a case where it is necessary to transfer a solution micro-sample. Also, there is a possibility that efficiency, sensitivity and treatment ability for obtaining a desired result in each of the fields tremendously increase due to such transfer. To achieve the transfer of a solution micro-sample, there are known ways utilizing, for example: transferring a sample by a pressure from the outside on the assumption that a fine channel formed on a substrate is used; transfer by static electricity; electrowetting; utilizing a change of volume or formation of air bubbles by heating; electroosmosis flow; and the like.
However, in order to transfer a solution micro-sample by such means, it has been necessary to form a fine groove on a substrate by utilizing micromachining technology and/or to arrange components such as an electrode, a heater, etc. Also, in forming a channel, bonding between substrates to each other has been necessary. Furthermore, in the case of transferring a sample by a pressure from the outside, not only auxiliary parts such as a pump, a conduit, etc. are necessary, but also a so-called dead volume increases, and therefore, there has been limits in miniaturization of a measurement system or the like for achieving a reduction in the amount of the sample.
On the other hand, as a method for analyzing a solution micro-sample, paper chromatography utilizing an infiltrating effect of an aqueous solution into filter paper has been known. As means for detecting a biological substance, which is simple and easy and inexpensive, the immunochromatography method has been developed and improved (see, for example, Patent Document 1). Also, a measurement chip in which filter paper is arranged in a plastic channel is disclosed as an analogous technology (see, for example, Non-Patent Document 1).    Patent Document 1: Japanese Patent Publication No. 07-36017;    Patent Document 2: Japanese Patent Laid-Open No. 2001-89134;    Patent Document 3: Japanese Patent Laid-Open No. 2004-250290;    Non-Patent Document 1: J-E. Kim, et al, Anal. Chem., 2005, 77, 7901-7907.